[FIX] List of minor fixes to be made to the development branch

[ravinkohli]

These are some of the minor fixes to be made to the development branch.

• N_threads in API module.
• Dropout Shape in ShapedResNetBackbone. these lines.
• Fixes in shake drop and shake-shake utils. See this and this
• Fixes in fully connected head config space. See this
• Xaviar_normal in Xavier. Here
• Add test loader in base_data_loader and add random state. Here
• Predict_proba in pipeline tabular classification. Here